General :: Ubuntu - 3 Monitor PCI-e Graphics Card?

the only way to get multiple monitors AND compositing (Compiz) on Linux is to use a single graphics card that can drive both (or in my case all three) screens. I bought a Radeon 5750 specifically because it claims to able to drive 3 monitors. I can plug in 3 monitors (2 DVI, 1 HDMI) and the Catalyst Control Center shows all 3, but only 2 can be enabled at a time.

The exact message is:

The current settings cannot be applied. Possible issues may include:
- Display(s) cannot be enabled.
- Setting(s) cannot be applied due to insufficient video memory.

So I'm going to assume that either the 5750 doesn't support 3 monitors, OR, more likely, ATI couldn't be bothered to add that support to their Linux drivers. So this is a multipart question:

First, can anyone suggest a PCI Express Graphics card that can run 3 screens on linux without tremendous pain? I'm looking for something where you install the driver and all three screens "just work". Does such a card exist? Second, if you have a 5750, have you been able to get it to do 3 monitors? I'm running Ubuntu 10.04 at the moment. UPDATE: I got my active adapter in the mail today (it's DisplayPort to DVI) and so far things seem to be better. I can run my third screen, drag things seamlessly between them, and I am also running compiz. The adapter I'm using is a "B087B-005B" made by "Accell", UPC is "826388106239".

There's still a couple "annoyances" that need worked out though: The left most screen is always the primary monitor. Which means the "gnome bar" (is that what you call the applications-places-system menu?) is always on the left most screen. It also means that new dialogue boxes always opened centred on the left screen, which is counter intuitive. Especially if you're using a program like GIMP and the text editor or color picker pops up on the left. Does anyone know of a way to change it so that new windows always pop up on the center screen?